INDUSTRIAL BRUSH, APPARATUS AND METHOD FOR MAKING

SAID INDUSTRIAL BRUSH.

Technical field

This invention relates to an apparatus and a method for making an industrial brush, of the type known as "end brush" or "cup brush", less than 100 mm in diameter, and to the industrial brush itself.

The invention applies, more specifically, to the technical field of industrial and hobby brushes, that is to say, brushes used for machining processes (for example, deburring, lapping or polishing of surfaces, etc.)..

More specifically, the invention refers to "end brushes" or "cup brushes" (if small in diameter), as well as to individual components for making brushes which are large in diameter or for mounting in specific machine tools used in CNC machining centres.

Background art

These brushes are reduced in diameter and generally comprise a cup shaped body, extending mainly along a central axis, and a plurality of filaments or wires or cables having a portion which is fixed inside the cup and a portion which protrudes outwardly therefrom in order to apply a brushing action when the brush body is set in rotation about the central axis.

More precisely, the brush body comprises a cup having a substantially tubular containing portion which houses the filaments and a joining portion, generally defined by a pin defining the axis of rotation and protruding away from the grip portion.

In the prior art, these brushes are made in a predetermined succession of steps.

First of all, a coil of straight or crimped filaments is prepared which is unrolled in such a way that an end stretch of it is fed in a straight line parallel to its direction of extension.

At the same time, a cup is placed under the end stretch being fed. The cup is positioned perpendicularly to the filaments and is oriented in such a way that its receiving portion faces the filaments.

Next, the end stretch is stopped, so that the end stretch extends downstream of the cup centre line for a length substantially equal to the length to be obtained for the finished product.

A cutter then cuts the end section at a point upstream of the centre line in such a way that the lengths downstream and upstream of the centre line are substantially the same.

A plug extending transversely to the axis of the cup is placed at the centre line, and above the end stretch and forced by press means into the receiving portion of the cup, pushing the end section of the coil into the cup along with it.

That way, the end stretch substantially takes the shape of a "U", whose the two end portions extend in a straight line in a substantially parallel manner and whose intermediate portion has a curved shape and is located under the plug.

During the operation of the press means, a pair of swaging jaws locally tapers inwards an end zone of the receiving portion of the cup so as to hold the plug and the filaments within it.

To finish, a trimming tool acts on the ends of the filaments in order to level them off so they all extend beyond the cup for the same length.

Disadvantageously, brushes made in this way have several drawbacks. The main drawback is that the transversal plug which gives the filaments the "U" shape creates a hollow in the middle of the brush which considerably reduces brush functionality.

Further, this shape imparts to the filaments a preferential direction of deformation, that is to say, the two end portions are moved apart along a direction at right angles to the plug. This drawback, too, negatively affects the functionality of the brush because the area occupied by the filaments is irregular and leads to a non-uniform brushing action.

Furthermore, the use of filaments which have been deformed (bent by the press means) creates within each filament a chain of internal stresses which reduces brush durability. Moreover, inwardly tapering only the end of the cup may sever some of the filaments, a problem which may become critical in the case of very fine filaments (less than 0.25 mm in diameter). Also known in the prior art are machines for making end brushes with twisted bundles. In these machines, a loop is first formed around which a plurality of twisted bundles are wound. The loop is then inserted axially into the brush body and then fixed by beading a small pin located on the bottom of the cup so as to lock the loop with the twisted bundles which were positioned axially during insertion of the loop.

Disadvantageously, making brushes with these machines is a particularly laborious operation. Moreover, the use of twisted filaments or bundles (that is, cables) necessitates two completely different apparatuses, thus reducing the manufacturer's flexibility (or at best increasing manufacturing costs).

Aim of the invention

This invention has for an aim to provide an industrial brush and an apparatus and a method for making the industrial which overcome the above mentioned drawbacks of the prior art.

More specifically, this invention has for an aim to provide an apparatus and a method for making an industrial brush which are simple, rapid and economical.

Another aim of the invention is to provide a method for making an industrial brush suitable for producing an "end brush" or "cup brush" both with filaments or wires and with cables (known as twisted bundle or knot) with minimal retooling. A further aim of the invention is to provide a machine and a method for making end brushes which, if used for making standard end brushes (with the plug inside the cup) reduces manufacturing defects and production costs.

A yet further aim of the invention is to provide an industrial brush having uniformly distributed filaments or wires or cables with uniform behaviour and with very densely packed filaments or wires or cables.

A yet further aim of the invention is to provide an industrial brush which is simple to make and high in performance.

These aims are fully achieved by the industrial brush and the method for making it which form the object of this invention.

Brief description of the drawings

The features of the invention will become more apparent from the following detailed description of a preferred, non-limiting embodiment of it, with reference to the accompanying drawings, in which

- Figure 1 is a perspective view of an industrial brush according to this invention;

- Figure 2 is a cross section of the industrial brush of Figure 1 , showing the novel features of the cup in a first embodiment;

- Figure 2a is a cross section of the industrial brush of Figure 1 , showing the novel features of the cup in a second embodiment;

- Figure 2b is a cross section of the brush in a traditional form but with the innovative closure of the cup;

- Figures 3a-3c are cross sections of further embodiments of an industrial brush according to the invention;

- Figures 4a-4d are cross sections of different embodiments of a cup- shaped member used in the method according to the invention to make the brushes of the preceding figures;

- Figure 5 is a schematic view of an apparatus for making the industrial brushes according to the invention; - Figure 6 shows a detail from Figure 5;

- Figures 7a-7c show successive steps of the method for making the industrial brushes according to the invention implemented by the apparatus of Figure 5;

- Figure 8 is an exploded view of an embodiment of the press means used in the apparatus for making the industrial brushes according to the invention;

- Figure 8a shows a detail from Figure 8. Detailed description of preferred embodiments of the invention

With reference to the accompanying drawings, the numeral 1 denotes an industrial brush made using the method according to the invention.

More specifically, this specification expressly refers to brushes of the type known as "end brushes", suitable for use with electric or air tools, for example for deburring, cleaning surfaces, removing dirt or paint, brushing welding joints or oxidation points.

This invention might, however, also apply to other types of brushes.

In the embodiments illustrated, the axial extension of the brushes 1 is longer than their radial extension and for that reason, they are used for parts which are difficult to access: in corners or inside holes and for cleaning and polishing dies and moulds.

The method involves the use of a cup-shaped member 22 (defining a brush body 2 which is described in more detail below).

The cup-shaped member 22 has a containing portion 23 shaped to contain and hold within it lengths 8 of the filaments or wires or cables (metallic or plastic) 51 , and a joining portion 26 designed to be connected to a rotary power drive unit (not illustrated).

Preferably, the containing portion 23 of the cup-shaped member 22 has a bottom wall 24 and at least one side wall 25 which together define a receiving cavity "V".

Thus, the containing portion 23 is a box-like element extending along its central axis "A" and having an access opening "B" opposite to the bottom wall 24 to allow the filaments or cables 51 of the brush to be inserted.

In the preferred embodiment, the cup-shaped member 22 comprises a pin 12 extending inside the cavity "V" upwards from the bottom wall 24, preferably along a direction parallel to the central axis "A".

In the embodiments of Figures 4a, 4b and 4c, the side wall 25 of the cup- shaped member 22 is flared in shape (away from the bottom wall 24) to facilitate insertion of the bundle 7, as will become clearer as this description continues.

In other words, the cup-shaped member 22 has a flare 27 at an end zone 25a of the side wall 25.

Preferably, the flare 27 extends away from the bottom wall 24.

The flare 27 may be only on the inside face 25c of the side wall 25, only on the outside face 25d, or on both.

The method according to the invention also comprises preparing a cord 50 comprising a plurality of substantially parallel filaments or wires 51 (straight or crimped) having at least one end stretch 52 extending along a main direction "C".

Alternatively, the bundle 7 may comprise lengths of cables, made preferably of metal or plastic.

These cables are defined by a group of filaments 51 twisted round each other, preferably in a substantially helical manner.

The cord 50 might also comprise one or more wires.

Unless otherwise specified, reference will be made indistinctly either to one (filaments or wires) or to the other (cables) or to both, without limiting the invention.

It should be noted that the cord 50 has its own extension, which may differ from that of the end stretch 52. For example, it may be wound around a reel 102a or the like.

The end stretch 52, on the other hand, has a substantially straight-line extension, along the main direction "C", in such a way that it can be at least partly housed in the cavity "V" of the containing portion 3 of the brush body 2.

In other words, the plurality of filaments or wires 51 , which may be straight or crimped, are preferably kept in a substantially straight line so that they are easier to handle when they are later inserted in the cup-shaped member 22 and cut.

Where necessary, the plurality of filaments or cables 51 may be wrapped in a film of plastic material (for example, nylon or polythene) or by a mechanical system.

The method comprises first of all placing the cup-shaped member 22 so it faces the end stretch 52 of the long cord 50.

In a first embodiment of the method, the cup-shaped member 22 is aligned with the end stretch of the cord 50 along the main direction "C".

In other words, in this embodiment, the main direction "C" of the end stretch 52 is aligned with the central axis "A" of the cup-shaped member 22 (in particular, of the containing portion 23 thereof).

Advantageously, in this way, the receiving cavity "V" is made to face a free end 52a of the end stretch 52 itself.

Alternatively, in a second embodiment, whereby a standard end brushes are made, the cup-shaped member is made to face the end stretch 52 in such a way that the main direction "C" thereof is at right angles to the central axis "A" of the containing portion 23.

Next, the method comprises a step of generating motion whereby the end stretch 52 of the cord 50 and the containing portion 23 of the cup-shaped member 22 are moved towards each other in such a way as to insert the end stretch 52 into the receiving cavity "V".

More specifically, the motion generating step terminates when a portion of the end stretch 52 comes into abutment against the bottom wall 24 of the containing portion 23.

In the aforesaid first embodiment, the relative motion generating step comprises inserting the free end 52a of the end stretch 52 into the cavity "V" along the main direction "C". This step terminates when the free end 52a abuts against the bottom wall 24 of the containing portion 23.

Preferably, this step comprises feeding the end stretch 52 of the cord 50 along its main direction "C".

As mentioned above, feeding the end stretch 52 is stopped when its free end 52 reaches the bottom wall 24.

In the second embodiment, a plug (not illustrated) extending transversely to the axis of the cup is driven into the containing portion 23 and pushes the end stretch 52 of the cord 50 along with it.

That way, the end section 52 substantially takes the shape of a "U", where the two end portions extend in a straight line in a substantially parallel manner and an intermediate portion has a curved shape and is located between the plug and the bottom wall 24.

The method also comprises a step of separating the end stretch 52 from the rest of the cord 50 through the agency of cutting means 1 10 to define a bundle 7 of lengths 8 of filament or cable.

In the first embodiment of the method, this separating step is performed after the step of generating relative motion (that is, of feeding the cord 50). In the second embodiment of the method, on the other hand, this separating step is performed before the step of generating relative motion (that is, of inserting the plug).

The method preferably also comprises a step of radially deforming the side wall 25 of the containing portion 23 in order to define retaining means 0 whereby the bundle 7 is held within the cavity "V".

The expression "radially deforming" is used here to mean deforming the side wall 5 in such a way as to modify, in the deformed zone, the cross section of the cavity "V" transversely to the central axis "A" of the containing portion 23 (and thus to the main direction "C"

More specifically, the radial deformation step is such as to reduce the cross section of the cavity "V" at a working zone of suitable press means 11 1. Preferably, the radial deformation step comprises the step of forming a neck 1 1 of predetermined length "L" on the side wall 25 of the containing portion 23 in such a way as to define the retaining means 10 described above.

Preferably, the radial deformation step is performed on at least 1/3 (more preferably, at least half) of the length of the side wall 25. In other words, the length "L" of the neck 1 1 corresponds to at least 1/3 (preferably 1/2) of the length of the side wall 25.

More precisely, the method comprises a step of making a neck 1 1 on the side wall 25 of the containing portion 23, where the length "L" of the neck 1 1 corresponds to at least 1/3 of the length of the side wall 5 measured parallel to the central axis A,

In the preferred embodiment, the neck 1 1 has a length "L" corresponding to the side wall 5.

It should be noted that the neck 1 1 of predetermined length "L" is tubular in shape.

More precisely, the neck 1 1 of predetermined length "L" extends towards the end 25a of the side wall 25 (distal from the bottom wall 24) to partly define the retaining means 10.

In other words, the end zone 25a of the side wall 25 distal from the bottom wall 24 defines a passage which is smaller in cross section than the cross section at the bottom wall 24.

Preferably, the step of making a neck 1 1 is performed by radially deforming a plurality of sections of length "L", which are angularly (equi)spaced around the central axis A.

That way, a plurality of longitudinal ribs 16 are formed which are substantially parallel to the central axis "A" and alternated with a corresponding plurality of longitudinal channels 7.

Preferably, there are at least 3 of the above mentioned sections, and more preferably, six, eight, ten or twelve.

Alternatively, a plurality of longitudinal walls are formed which are substantially parallel to the central axis "A" and which are connected to each other by respective connecting edges.

In an embodiment whereby the brush illustrated in Figures 3a and 3b is made, the radial deformation step comprises a sub-step of radially deforming an intermediate zone 25b of the side wall 25 to make the narrowing 13 with a substantially annular section, as described above. Preferably, the radial deformation step is performed by an active portion 1 12 of the press means 1 1 1.

More preferably, the active portion (or swage) 1 12, which is made up of various segments, according to the diameter of the cup, and which can make diverse tapering forms (according to the shape of the segments of the swage or clamp and the length of the cup).

The swage or clamp 1 2 is described in more detail below.

In the preferred embodiment, the separating step and the radial deformation step are performed simultaneously (or in rapid succession) in such a way as to speed up production times.

The method also comprises a step of marking (or stamping or engraving) a plurality of product identification data on one or more outside faces 25d of the side wall 25 of the containing portion 23 of the cup-shaped member 22.

Preferably, this step is performed by specific press means 1 1 1. More preferably, the press means 1 1 1 are the same as those which perform the radial deformation step.

In other words, the active portion 1 12 comprises one or more dies 1 14 used for marking (or stamping). In the preferred embodiment, the marking step and the radial deformation step (by which the neck 1 1 is formed) are performed simultaneously through the agency of the press means 111. Discussed and described below in this regard is an apparatus 100 for making the industrial brush 1 according to the invention, preferably performing the steps of the method just described.

The apparatus 100 comprises a mounting and supporting frame 101 which a plurality of means for assembling the brush 1 are connected to, or at least operatively associated with.

More specifically, the apparatus 100 comprises means 102 for feeding the aforementioned cord 50 of filaments or wires or cables 51 , the means 102 being, as stated, associated with the frame 101.

As described above in connection with the method, the cord 50 has an end stretch 52 directed along a substantially straight main direction "C" corresponding to the direction of extension of the filaments or wires or cables 51.

In a first embodiment, the feed means 102 are configured to position the end stretch 52 along a working direction "D", preferably corresponding to the main direction "C".

In the embodiment illustrated (Figure 5), the feed means comprise a reel 102a with a first stretch 50a of the cord 50 wound around it and movable in rotation to unwind the cord along a straight conveyor 102b extending in the working direction "D".

The feed means might, however, take a different form, provided they are capable of placing an end stretch 52 of the cord 50 along the working direction "D" (corresponding to the main direction "C").

The apparatus 100 also comprises a housing unit 105 associated with the frame 101 and shaped to house at least one cup-shaped member 22, preferably of the type described above.

The housing unit 105 thus comprises at least one housing 105a dimensioned to receive the cup-shaped member 22. Preferably, the housing unit 105 has a gripping portion configured to hold the cup-shaped member 22 within it.

The housing unit 105 is configured to align the cup-shaped member 22 with the end stretch 52 of the cord 50 in a work plane.

In the first embodiment of the apparatus (illustrated in Figures 5 and 6), the housing unit 105 and the feed means 102 are positioned in such a way that the end stretch 52 of the cord 50 (and hence the working direction "D") is parallel and aligned with the central axis "A" of the cup-shaped member 22 (and hence with a central axis of the housing).

Thus, the receiving cavity "V" is made to face a free end 52a of the end stretch 50 itself.

Preferably, the apparatus 100 comprises a drive unit 103 configured to move the housing unit 105 in such a way that the central axis "A" of the cup-shaped member 22 is aligned with the main direction "C" (and hence with the end stretch 52).

More precisely, the central axis "A" is aligned with the working direction "D".

In the embodiment illustrated in Figure 5, the drive unit 103 is defined by a rotary table 104.

The table 104 is provided with a plurality of gripping elements defining the housing unit 105.

Each gripping element is thus movable in rotation between a loading position, where it receives the respective cup-shaped member 22 from a supply station, and an unloading station, where it releases the finished brush 1 (and thus releases the brush body 2) to a collecting station.

Between the two positions there is an assembly position, located in an operating zone "Z" of the apparatus 100, where the cup-shaped member 22 and the bundle 7 (described above) are assembled.

It should be noted that the operating zone "Z" is aligned with the working direction "D".

Alternatively, in a second embodiment not illustrated, the housing unit 105 and the feed means 102 are positioned in such a way that the end stretch 52 of the cord 50 (and hence the working direction "D") is at right angles to the central axis "A" of the cup-shaped member 22 (and hence to a central axis of the housing).

Preferably, the apparatus 100 comprises means 107 for generating a relative motion, associated with the feed means 102 and configured to move the end stretch 52 of the cord 50 and the cup-shaped member 22 towards each other in such a way that the end stretch 52 is inserted into the receiving cavity "V" of the cup-shaped member 22.

In the first embodiment of the apparatus 100, the motion generating means 107 operate along the working direction "D" (which, as already stated, corresponds to the main direction "C").

In other words, the motion generating means 107 are configured to insert the free end 52a of the cord 50 into the cavity "V".

Thus, the motion generating means 107 produce a movement by which the cup-shaped member 22 and the end stretch 52 move towards each other by a predetermined distance.

Preferably, the relative motion generating means 107 comprise a feed unit 108 operating along the working direction "D" and configured to pull the end stretch 52 of the cord 50 towards the cup-shaped member 22 (that is, towards the operating zone "Z").

The feed unit 108 comprises at least one gripping element 109a, 109b movable along the working direction "D" (that is, along the main direction "C") to insert the end stretch 52 of the cord 50 into the cavity "V" of the cup-shaped member 22.

Preferably, the feed unit 108 comprises a pair of gripping elements 109a, 109b (a first 109a and a second 109b) movable along the working direction "D" and able to be operated selectively to work alternately in such a way that at least one of them keeps its hold on the end stretch 52 of the cord 50.

The advantage of this feature is explained in more detail below.

Alternatively, in the second embodiment, the motion generating means operate transversely to the main direction "C" and are equipped with pushing means to insert the end stretch 52 into the cavity "V" in a U- shaped configuration.

Preferably, in order to improve its operation, the apparatus comprises a bundle wrapping station 1 16 through which the cord 50 is made to pass by the feed unit 108. The bundle wrapping station is configured to pack the cord 50, in particular its end stretch 52, in a sheet of plastic material (for example, nylon or the like).

Advantageously, this allows increasing the density of the filaments or wires 51 (or cables) and the stiffness of the cord 50.

In order to perform the separating step described above in connection with the method according to the invention, the apparatus 100 also comprises cutting means 110 associated with the frame 101 and operating transversely to the working direction "D" to separate the end stretch 52 from the rest of the cord 50 to make a bundle 7 of lengths 8 of filaments or wires or cables 51.

Preferably, the cutting means 110 comprise a guillotine 110a or a cutter, movable (radially) towards and away from the cord 50.

It should be noted that bundle wrapping the cord 50 in the bundle wrapping station 116 or using a previously wrapped cord of filaments or wires or cables facilitates cutting and insertion into the cup cavity.

In effect, bundle wrapping the cord in the sheet of plastic material (or by alternative systems) allows the cord 50 to be precisely fed and its end stretch 52 precisely inserted into the cavity "V" and quickly and neatly cut off

In the first embodiment, the guillotine 10a is interposed between the first gripping element 109a and the second 109b in such a way that even after being separated from each other, the cord 50 and the bundle 7 are "controlled" and held in position.

Advantageously, therefore, both the bundle 7 and the rest of the cord 50 are constantly guided, thereby increasing working precision

Preferably, the apparatus 100 also comprises press means 111 associated with the housing unit 105 and having an active portion 1 2 of predetermined length "L" that is radially movable to radially deform the side wall 25 of the containing portion 23.

Thus, the press means 11 form a neck 11 of length "L" corresponding to at least 1/3 of the length of the side wall 25 of the containing portion 23, measured parallel to the central axis "A".

Preferably, the press means 111 operate (that is, they are mounted) at the operating zone "Z".

Preferably, the active portion 112 comprises at least three jaws 113 of predetermined length "L" which are angularly (equi) spaced and radially movable towards and away from each other between a rest position, where they are away from each other, and an operating position, where they are close to each other.

In the embodiment illustrated, the jaws are eight in number but they might also be six, ten or twelve in number, depending on the size of the brush to be made.

Preferably, at both the rest position and the operating position, the jaws 113 are circumferentially spaced from each other by a gap 117 defining a radial escape route for the deformed material.

As illustrated in Figure 8, the active portion 112 of the press means 111 comprises an actuator member 118 associated with the jaws 113 to move them between the rest position and the working position.

Preferably, the actuator member 118 is rigidly connected to the jaws 113 by reversible connecting means (for example, screws or the like) in order to allow the jaw 113 to be replaced.

In the embodiment illustrated, the actuator member 118 is a cylindrical element (preferably with two or more sectors 119) having a conical inside surface, so that a relative axial movement between the jaws 113 and the actuator member 118 causes the jaws 113 to move radially between the rest position and the operating position to produce a tightening action. In order to make the above mentioned engravings 15, the press means 111 comprise at least one marking die 114 with, stamped on it, the plurality of identification data of the brush 1.

The die 114 is movable transversely to the working direction "D" between a rest position and a marking position in order to stamp the plurality of data on the outside face 5d of the side wall 5 of the containing portion 23 of the cup-shaped member 22.

To manage the assembly operations, the apparatus 100 comprises a control unit 1 5.

The control unit 15 is associated with the cutting means 110 and with the press means 11 , and is configured to activate them simultaneously (or in rapid succession) in order to speed up the production times of the brush 1. Preferably, the active portion 112 and the die 114 operate simultaneously. The control unit 115 is also associated with the feed means 102 and with the housing unit 105 in order to coordinate the production sequence to make it rapid and efficient.

Structurally, the brush 1 made using the method according to this invention comprises a brush body 2 with a containing portion 3 shaped to contain and hold within it a plurality of filaments or wires or cables (metallic or plastic) 51 , and a joining portion 6 designed to be connected to a rotary power drive unit (not illustrated).

It should be noted that the brush body 2 is nothing other than the cup- shaped member 22 after being processed according to the method of the invention

Thus, the containing portion 3 of the brush body 2 is cup shaped and has a bottom wall 4 and at least one side wall 5 which together define a receiving cavity "V".

In other words, the containing portion 3 is a box-like element extending along its central axis "A" and having an access opening "B" opposite to the bottom wall 4 to allow the filaments or cables 51 of the brush to be inserted.

The access opening "B" is delimited by an end zone 5a of the side wall 5 distal from the bottom wall 4.

Thus, at the initial stage of production, the side wall 5 has a substantially tubular shape.

The containing portion 3 preferably has a symmetrical shape, so that the action of the brush 1 during its rotation about the central axis "A" of the containing portion 3 remains uniform.

In the embodiment illustrated, the geometry of the containing portion 3 is made up of various sections, all perpendicular and substantially symmetrical about the central axis "A". These sections may take different shapes and sizes so as to hold the filaments or wires or cables securely even at the maximum rotation speeds, or the bottom wall 4 is substantially circular, whilst the side wall 5 has a tubular, substantially tapered shape. In other embodiments, however, they might also have polygonal (axisymmetric), or even partly prismatic, shapes, so as to securely hold the filaments or wires or cables according to constructional features (crimping, density, etc. of filaments or wires).

Preferably, the joining portion extends in a substantially coaxial manner to the containing portion 3

Thus, the joining portion 6 also extends along the central axis "A".

In the embodiment illustrated, the joining portion 6 comprises a shank 6a extending from the bottom wall 4, away from the containing portion 3, preferably along the central axis "A".

Alternatively, in the embodiment illustrated in Figure 4d the joining portion may be defined by a port 26b located at the bottom wall 4 and able to be coupled to a rotary drive shaft of the motor. The port 26b is preferably a threaded hole.

In the preferred embodiment, the brush body 2 is made of a metallic material, preferably steel, stainless steel, brass, bronze or copper (depending on what the brush is to be used for).

The brush 1 also comprises a bundle 7 of lengths 8 of filaments or wires (metallic or plastic), partly housed in the cavity "V" and partly protruding therefrom.

Similarly to what was mentioned above, the bundle 7 may comprise lengths of wires or cables, made preferably of metal or plastic.

These cables are defined by a group of filaments 51 twisted round each other, preferably in a substantially helical manner.

In an embodiment obtained with the first embodiment of the method, each length 8 of filament or wire or cable extends between its first end 8a which is positioned outside the receiving cavity "V" and its second end 8b which is opposite to the first end 8a and which abuts the bottom wall 4 of the containing portion 3 of the brush body 2.

Thus, the bundle 7 of lengths 8 of filaments or wires or cables in turn extends between its first end 7a (corresponding to the first end 8a of the lengths 8 of filaments or wires or cables) which is positioned outside the receiving cavity "V" and its second end 7b which abuts the bottom wall 4 of the containing portion 3.

In other words,, each length 8 of filament or wire or cable extends along the central axis "A" of the containing portion 3 and is divided into two half parts: a first half part 9a positioned inside the cavity "V" and terminating with the aforesaid second end 8b abutting against (that is, in contact with) the bottom wall 4 and a second half part 9b positioned outside the cavity "V" and extending from the first half part 9a and away from the same to define a bristle of the brush 1.

Preferably, the filaments or cables 51 are made of metallic or plastic material.

In order to keep the bundle 7 inside the cavity "V", the brush 1 comprises retaining means 10.

These retaining means 10 are characterized by innovative forms made possible by the novel apparatus (and method) according to the invention, which allows the possibility of applying this method also to the production of traditional end brushes (plug driven into the cup (see Figure 2b).

Preferably, the retaining means 10 are at least partly defined by a neck 11 of predetermined length "L" formed on the side wall 5 of the containing portion 3.

More precisely, the side wall 5 of the containing portion 3 has at least one portion of length "L" extending towards the central axis "A". Thus, an end zone 5a of the side wall 5 distal from the bottom wall 4 defines a passage which is smaller in cross section than the cross section at the bottom wall 4. In other words, the side wall 5 has a tapered shape. It should be noted that the side wall 5 may be tapered along the full length "L" or only partly, so it is inclined towards the central axis "A" to form the neck 11.

The neck may also have the same size along the full length "L" following a discontinuous narrowing of the cross section (stepped type).

Preferably, the side wall 5 is tapered for at least 1/3 (more preferably, at least half) of its length. In other words, the length "L" of the neck 11 corresponds to at least 1/3 (preferably 1/2) of the length of the side wall 5. Advantageously, the neck 11 partly deforms the filament lengths 8, compressing them against each other so as to prevent them from coming out of the cavity "V".

Preferably, the side wall 5 of the containing portion 3 comprises a plurality of longitudinal ribs 16, which are substantially parallel to the central axis "A" and angularly spaced from each other so as to define a corresponding plurality of longitudinal channels 17.

In the embodiment illustrated, the ribs 16 (and hence the channels 17) are angularly equispaced.

The channels 17 are preferably inclined at an angle to and towards the central axis "A" to define the neck 11.

Alternatively, (taking the preceding condition to a limit), the neck 11 is defined by a plurality of longitudinal walls substantially parallel to the central axis "A" and connected to each other by respective connecting edges.

In a first embodiment (illustrated in Figure 2), the containing portion 3 has a middle pin 12 extending inside the cavity "V" upwards from the bottom wall 4 along a direction parallel to (preferably coinciding with) the central axis "A" of the containing portion 3.

The pin 12 partly defines the retaining means 10. More precisely, the pin 12 acts in conjunction with the neck 1 to reduce the cross section size of the passage for the lengths 8 of filaments or cables, thus deforming them and increasing the retaining action thereon. In effect, it should be noted that the pin 12 is substantially a complement to the neck 11. That is because the neck reduces the cross section size of the passage into the cavity "V" at a peripheral zone thereof, in the proximity of the access opening "B", while the pin 12 reduces the cross section size of the passage in a central zone of the cavity "V" in the proximity of the bottom wall 4.

In other words, the joint action of the neck 11 and the pin 12 creates a mechanical grip on the bundle 7, preventing it from coming out and improving its stability during its use in rotation (at high speed).

Preferably, the pin 12 extends for a length greater than 2/3 of the length of the containing portion 3 starting from the bottom wall 4.

In an alternative embodiment (illustrated in Figures 3a and 3b) the side wall 5 of the containing portion 3 has a narrowing 13 in its cross section, preferably annular in shape, at an intermediate zone 5b of it, preferably along the neck 11.

The narrowing 3, too, partly defines the retaining means 10.

Preferably, the narrowing 13 is defined by a protuberance 13a (or apex) on an inside face 5c of the cavity "V" of the side wall 5 and corresponding to a furrow 13b on an outside face 5d of the cavity "V".

In other words, the side wall 5 has a substantially circular (or polygonal) groove on its outside face 5d corresponding to an annular ridge on its inside face 5c.

It should be noted that, in some embodiments not illustrated, the retaining means 10 are defined jointly by the narrowing 13, the neck 11 and the pin

12

It should be noted that the retaining means might be defined by the neck 11 only.

Preferably, the side wall 5 of the containing portion 3, at its end portion 5a, has a flare which faces inside the cavity "V".

The flare facilitates insertion of the bundle 7 into the cavity "V" during assembly of the brush 1.

In effect, it should be stressed that the bundle 7 of lengths 8 of filaments or cables has a transversal cross section which substantially corresponds to that of the cavity "V", so that the retaining means 10 apply a compressive action such as to deform the single filament lengths 8 and compress them against each other.

Preferably, also, the brush body 2 (and, in particular, the containing portion 3) has a plurality of engravings 15 made on the outside face, representing a plurality of identification data of the product (that is, of the brush 1), such as, for example, technical specifications, production and safety data or the like.

It should be noted that the engravings 15 are located in such a way as to extend mainly parallel to the central axis "A" of the containing portion 3. Advantageously, full product details can thus be provided, independently of the diameter of the containing portion 3, since the information runs along the product length, along the main axis "A", which remains substantially constant.

The invention achieves the set aims and brings important advantages.

Indeed, the industrial brush made in this way, where the neck is formed along a large part of the length of the side wall, considerably reduces the stresses on the material, allowing better retention of the filaments or cables.

Moreover, the radial deformations are easy to obtain and it is very easy to substitute the press segments to vary the geometrical shapes of the neck. In effect, thanks to the method according to the invention, each length of filament has one end in abutment against the bottom wall of the cup, and thus has uniform structural and mechanical characteristics to allow uniformity in the machining processes the brush is used for.

Further, the use of substantially straight filaments (without bends) held in place by the tapered zone improves the durability of the filaments and makes them less subject to breaking.

Besides, the method according to the invention makes it possible to pack the filaments (or wires or cables) more densely in the brush cup.

It should also be noted that the production method according to the invention is not only appreciably faster and more efficient than those of the prior art but also more economical because it has fewer steps.

Furthermore, the apparatus for implementing the method is also simpler and more compact in structure.